Con log:"Seting up methods" from:"Boolean".

Repl methodIn: Boolean.
neg   [
   ^self ifTrue:[||^false] else:[||^true].
]
Repl methodIn: Boolean.
|: x[
   ^self ifTrue:[||^true] else:[||
      ^x ifTrue:[||^true] else:[||^false]
   ]
]
Repl methodIn: Boolean.
&: x[
   ^ ((self neg) | (x neg)) neg.
   ]
Repl methodIn: Boolean.
^: x[
   ^ (self | x) & ((self & x)neg)
]
Repl methodIn: Boolean.
toString[
   ^ self ifTrue:[||^"true"] else:[||^"false"].
]
